The present invention relates to the art of fabric dyeing and more particularly to a process for continuously dyeing long lengths of fabric. The present invention is also directed to a novel aqueous dye-accelerant composition for effectively and rapidly reacting a dye with the fibers of a textile substrate.
Over the years four chief techniques have been developed to the application of applying dyes to textiles. In one case, the dye liquor is moved as the material is held stationary. In another case, the textile material is moved without mechanical movement of the liquor, such as, for example in a Beck dyeing machine. In another case, the textile material is moved along with the mechanical movement of the liquor. Finally, a substantially non-mechanical dyeing process has been developed which is typically referred to as exhaustion. However, these conventional methods of applying dyes have many disadvantages, including, the length of time required to dye and fix the dye in the fabric; and the discoloration or, more particularly, shade variation of the dye which can result by their use.
For example, continuous processes for dyeing fabrics with reactive, direct, vat or dispersive dyes by padding methods are established in the art as are discontinuous methods, such as the batchwise exhaustion method. However, both conventional continuous and semi-continuous methods for dyeing fabrics have distinct disadvantages with regard to the appearance of the dyed material, and the time required to complete the dyeing process. For instance, semi-continuous dyeing of fabrics with fiber-reactive dyes by the cold pad-batch method gives rise to crease marks due to the plaiting of the impregnated material in boxes, which greatly reduces the quality of the finished article.
In addition, the dyeing times and fixing times for both techniques are on the order of hours, making efficient dyehouse management very difficult. A further disadvantage of conventional dyeing processes is that they are environmentally harmful. For example, conventional cellulose reactive dyeing processes generate large amounts of highly colored effluents containing high concentrations of electrolyte (up to 100 g/l) and alkali.
Accordingly, a need exists for a method of dyeing fabric that rapidly, economically, ecologically and uniformly distributes a small amount of dye throughout the substrate with no required waiting period.
In an embodiment according to the present invention, a dye accelerant chemical, comprising a novel aqueous dye-accelerant composition is provided. The dye-accelerant composition comprising: an organic solvent; at least one dispersing agent; a chelating agent; and a vehicle.
In an alternative embodiment, the dye-accelerant composition comprises about 0.5 to 5% by weight of an organic solvent, about 10 to 20% by weight of at least one dispersing agent, about 0.5 to 10% by weight of a chelating agent; more preferably about 0.5 to 2% by weight of an organic solvent, about 10 to 20% by weight of at least one dispersing agent, about 0.5 to 5% by weight of a chelating agent, and about 50 to 99% by weight of a vehicle; and even more preferably about 1% by weight of an organic solvent, about 15% by weight of at least one dispersing agent, about 3% by weight of a chelating agent, and about 80% by weight of a vehicle.
In still another embodiment, the organic solvent is an organic compound having a low vapor pressure, such as a lower alcohol. In such an embodiment, the lower alcohol may be selected from the group consisting of: methanol, ethanol, propanol, isopropanol, butanol, and isobutanol.
In yet another embodiment, the dispersing agent is one or more surfactants selected from the group of: noionic, anionic, cationic, ampholytic, and zwitterionic surfactants. Preferably, the dispersing agent is one or more surfactants selected from the group consisting of: nonionic and anionic surfactants, and even more preferably the dispersing agent is a combination of both an anionic and nonionic surfactant. In such an embodiment, the composition comprises about 5 to 20% by weight of a nonionic surfactant and about 0.5 to 5% by weight of an anionic surfactant, more preferably about 10 to 15% by weight of a nonionic surfactant and about 0.5 to 2% by weight of an anionic surfactant, and even more preferably about 13% by weight of a nonionic surfactant and about 1% by weight of an anionic surfactant. In such an embodiment, the dispersing agent may be selected from the group consisting of: carboxymethylcellulose, hydroxypropylcellulose, alkyl aryl sulphonates, long-chain alcohol sulphates (primary and secondary alkyl sulphates), sodium sulphates, sodium alkyl sulphates, sodium aryl sulphates, sulphonated olefins, sulphated monoglycerides, sulphated ethers, sulphosuccinates, sulphonated methyl ethers, alkane sulphonates, phosphate esters, alkyl isethionates, acyl sarcosides, alkyl taurides, fluorosurfactants, fatty alcohol and alkyl phenol condensates, fatty acid condensates, condensates of ethylene oxide with an amide, condensates of ethylene oxide with an amide, block polymers (polyethylene glycol, polypropylene glycol, ethylene diamine condensed with ethylene or propylene oxide), sucrose esters, sorbitan esters, alkylomides, ethoxylated amine polymers and mixtures thereof. In a preferred embodiment, the dispersing agent is a combination of an alkyl phenol ethoxylate and a sodium alkyl sulphate, and in an even more preferred embodiment the dispersing agent is a combination of nonylphenolethoxylate and sodium naphtalene sulphate.
In still yet another embodiment, the chelating agent is selected from the group consisting of: aminocarboxylic acids, hydroxyaminocarboxylic acids, hydroxycarboxylic acids, phosphates, di-phosphates, tri-phosphates, higher poly-phosphates, pyrophosphates, zeolites, polycarboxylic acids, carbohydrates (polysaccharides), hydroxypyridinones, organic compounds comprising catechol groups, organic compounds comprising hydroxymate groups, silicates or polyhydroxysulfonates. In such an embodiment, the chelating agent may be selected from the group consisting of: EDTA (ethylene diamine tetra-acetic acid), DTPA (Diethylene triamine pentaacetic acid), NTA (nitrilo triacetic acid), HEDTA (hydroxyethylene diamine tetra-acetic acid), DEG/DHEG (dihydroxyethyl glycine), HEIDA (N-(2-hydroxyethyl)-iminodiacetat), gluconic acid, citric acid, tartaric acid, oxalic acid, diglycolic acid, PBTC (phosphonobutantriacetat), ATMP (aminotri(methylenphosphonic acid), DTPMP (diethylene triaminpenta(methylenphosphonic acid), maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, and citraconic acid.
In still yet another preferred embodiment, the vehicle is water.
In still yet another embodiment, the composition further comprises an electrolytic salt. In such an embodiment, the electrolytic salt may be a combination of caustic soda and sodium bicarbonate.
In still yet another embodiment, the dye-accelerant composition comprises: about 1% by weight of isopropyl alcohol; about 13% by weight of alkyl phenol ethoxylate; about 1% by weight of sodium alkyl sulphate; about 3% by weight of DTPA; and about 80% by weight of water.
In still yet another embodiment, a dyeing process utilizing the dye-accelerant composition is provided, which includes five primary treatment processes: a pre-treatment process, a bleaching process, a neutralize and dye accelerant process, a dyeing process, and a dye stop or fixing process.
In still yet another embodiment, the concentration of dye accelerant used in the dyeing process is maintained at a specified percent automatically. In such an embodiment the mechanism for automatically controlling the percent concentration of dye-accelerant utilized in the process may include an automatic injection apparatus linked in a feedback system to a quantitative dye-accelerant analysis apparatus.